It has become a common sight when I’m travelling for work: A box of used prosthetic components, tucked away in a supply closet or strewn about a floor as someone from the clinic sifts through them to see what is usable.
That box is at the heart of two questions commonly asked of us at D-Rev, a nonprofit product development firm that designs and delivers products to people living on less than $4 a day: “Why do you sell products rather than donate them?” and “Why is a market approach better than the alternatives?” In the case of our $80 ReMotion prosthetic polycentric knee joint, the alternatives are providing donated, used devices from a higher-income market, such as the United States, or for D-Rev to donate its product to end users.
To answer these questions, we need to understand the problem. The inability to access a quality prosthesis is a reality for most low-income patients around the world, either because products are unaffordable or care is unavailable. To begin to address this problem, a product needs to be accessible, fit the user’s needs and goals, and be durable in the user’s environment.
Reused and donated devices may be affordable, but finite quantities keep them from being fully accessible in these markets, and they fall even further short of the latter two conditions. Extreme differences in environmental conditions and usage can render the most high-performance device unsuitable and unusable. Through our work in a number of developing countries, we have learned that patients’ primary goals are to leave their homes, move freely in their communities, and return to work. This often means walking outdoors for long stretches on dusty streets with no options for cover when it starts to rain, or working outdoors in a flooded field. A repurposed product is not able to address the problem as it was never intended for this scenario, and we instead need to employ low-cost prostheses designed specifically for the target user’s environment, activities, and culture.
While the argument to design prostheses specifically for the target patients may be obvious, the argument to sell those products rather than donate them may be less clear. A donated knee would be the most affordable option for a clinic, but affordability alone does not mean accessibility. To truly be accessible, a product needs to also be available in sufficient quantities, easy to order, and reliably delivered. A donation approach would severely limit the number of users to whom devices could be provided. With that model, D-Rev would only be able to donate as many ReMotion Knees as it could afford to produce and ship with donations received from foundations or individuals; this is not a sustainable or scalable model.
A device that is sold at an affordable price to a prosthetic clinic does not suffer the same limitations. In our market-driven model, the manufacturing, distribution, quality control, and every other cost that goes into getting the product to the end user is covered by the price of the knee. This allows for scalable growth in the sales and distribution of the knee to clinics serving amputees, with no limit based on funds received. Most importantly, it keeps us accountable to our end users—a poorly designed product that does not provide value or address users’ needs could still be donated but would not continue to sell. Sales provide us with a feedback loop and act as a better measure of adoption than donations would; we know that clinics that continue to purchase our product value it.
This approach, however, depends on developing a knee that is both affordable and effective. By directing philanthropic activities to reduce the cost of the knee rather than subsidizing it long term, my D-Rev colleagues and I feel that we can help the most people in the most sustainable, scalable manner.
Vin Narayan, MS, earned a master’s degree in management science and engineering from Stanford University, California, with a concentration in entrepreneurial design. He joined D-Rev’s ReMotion project after co-designing a low-cost prosthetic elbow in a Stanford University course on medical device design.
